Lock guard



.April 12, 1932. L, oss 1,853,456

' LOCK GUARD Filed Dec. 30, 1929 Z'Sheets-Sheet l INVENTOR,

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A TTORNEY5.

April 12, 1932. oss 1,853,456

LOCK GUARD Filed Dec. 30, 1929 2 Sheets-Sheet 2 a d6 07 a J2 /0 I I C A? 54 i ll 70 w/fi/zs A 7 INVENTOR, fw'dozzz. Pass.

A TTORNEYS Patented Apr. 12, 1932 PATENT OFFICE GORDON L. B088, 01 KANSAS CITY, IISSOURI GUARD Application Med December 80, 1929. Serial 80. 417,889.

This invention relates to looks and has for its prima object the rovision of novel means com inable with t e lock mechamsm for precluding any form of tampering on the 6 art of ersons other than those holding the key to the lock.

One of the major objects of this invention is to provide a lock mechanism which has as a part of its structure novelly formed front 10 and strike plates which co-act when the lock is in the closed position to guard the latch bolt against tampJering.

Another ject of the present invention 1s to provide latch-bolt guards for locks which 15 may either be formed into the various parts of the lock as the same is bein manufactured or which may be added to t e lock mechanism or plates forming a part thereof, after the same has been mounted and even after the same has been in use for a length of time.

It is well known in this art that locks having bevelled latch-bolts are susceptible of unauthorized opening by sharp instruments which might be introduced in various manners between the front plate and the strike plate of the lock in such a fashion as to force the latch-bolt of the lock to the unlocked position where the lock is rendered valueless.

Still another object of this invention is to provide specifically formed front plates and strike plates for locks havin latch-bolts, which will combine in an efiective manner to protect the latch-bolt against'tampering.

An even further object of the present invention is to provide novel structure in a lock mechanism which will combine therewith to fully protect, and practically house the latchbolt which bridges the small gap between the front plate and strike plate.

A et further object of this invention is to provide the well known standard looks with simple, inexpensive and effective means for protecting the bevelled latch-bolt against tarlxxifering. inor objects will appear during the course of the detailed specification referring to the accompanying drawings wherein the preferred and two modified forms of the invention are illustrated, and wherein Figure 1 is a perspective fragmentary view showing a lock having parts made in accordance with this invention in place and ready for use.

Fig. 2 is a central horizontal cross-section through a lock made in accordance with this invention showing the entire lock assembly in the closed position.

Fig. 3 is a detailed perspective view of the strike plate made in accordance with this invention showing the rear side thereof and showing the same entirely removed from the operative position.

Fig. 4 is a vertical central section of the 'novel parts of the lock taken on line IV-IV of Fig. 2.

Fig. 5 is a perspective view of a modified form of strike plate made in accordance with this invention.

Fig.6 is a pers ective view of still another modified form 0 the invention showing an attachable strike plate housing which may be aflixed to the conventional strike plate to project there-from in a manner which will protect the latch-bolt against tampering, and

Fig. 7 is a detailed perspective view of the lock front plate made in accordance with the preferred form of the invention shown in Fi 1 to 4.

ike reference characters refer to similar parts through-out the several views and the numeral 8 indicates a door which carries the lock mechanism 10 of the well known and conventional type which is equipped with any form of latch-bolt 12 which maybe moved to and from the locked position through the use of the ordinary key not here shown. As is customary, latch-bolt 12 has a bevelled face 14, the outer-most edge of which engages strike plate 16 when the door is closed. The lock 10 should be equipped with a novelly constructed front plate 18, through which is formed an opening for the passage of latchbolt 12. In the preferred form of this invention latch plate 18 and strike plate 16 are novelly formed in a manner which will positively protect latch-bolt 12. When the parts of the lock are in the closed or locked position with the latch-bolt 12 extending through opening 20 of front plate 18 into opening 22 of strike plate 16, the latch-bolt 12 should be completel housed to preclude engaging itthrough t e use of any tampering instrument which may be inserted. from any point between the door 8 and the door casing 24 which supports strike plate 16. As is customary, a molding 26 limits the movement of door 8 as the same is being closed to a position where the latch-bolt 12 engages the opening 22 housed by these flanges when the door is closed and the mechanism is in the locked position. Flange 28 formed around the sides of the periphery of opening is of a size which will permit its passing between the walls of the flange formed around three sides of the opening 22 formed'in strike plate 16. The relation of these flanges is clearly shownin Fig. 1 and clearance between plates 18 and 16 should be such that the space between the plates will be entirely bridged by flanges 28 and 30 which are disposed in a telescoping fashion as shown in Fig. 4 when the s are in the locked position. A box like housing 32 integral with strike plate 16 extends outwardly from the side thereof opposite flange 30. It is into this housing 32.that the bevelled end of latch-bolt 12 projects when the parts are locked.

To further render latch-bolt 12 inaccessible to tampering tools, front plate 18 and strike plate 16 are each provided with a projecting wall 34 and 36 respectively adjacent each end thereof. These walls should be slightlv arched as shown in the drawings and should be wide enough to over-lap as shown in Fig. 4 when the door 8 is closed. Strike plate 16 is also provided with a longitudinal side wall v 38 which may extend any predetermined distance above and below the ends of strike plate 16. This wall 38 is mortised into the door casing 24 to over-lap the joint between the casing and molding 26.- The advantage of this is obvious.

In the modified form of the invention shown in Fig. 5 the construction of the strike plate is somewhat the same as the construction of the )similar plate shown in the preferred form with the exception that the housing 32 is omitted and the longitudinally extending side wall 52 may be made any predetermined length to extend above and below strike plate 50 to guard'the joint betwe n therethrough; outturned flanges molding 26 and casing 24. Projecting walls 54 disposed at each end of the strike plate 50 serve to protect the latch-bolt and this form of strike-plate may be added to any lock assembly without changing the front plate of the lock mechanism earned my the door.

Where it is desired to equip a strike plate with a device for protectm the latch-bolt which engages the same wit out losing the use of the strike plate, the device shown in Fig. 6 may be used. This modified form is sim 1y a housin 7 0 made in the form shown so t at'it may he soldered or otherwise affixed to the strike plate or to the casing by screws after the material behind the strike plate in use has been removed so that the hous- 1ng70 may be forced through the opening in the strike plate to a point where the face thereof stops along line 72. Thus a housing is formed behind the strike plate and flanges around three sides of its opening are provided which protects the latch-bolt against engagement by any shar tampering tool:

It is understood that t is invention might be embodied .in many different types of locks and that the parts made in accordance with this invention may be made up from an desirable material and formed in any fas on and while the preferred and two modified forms of the invention have been shown and described, it is desired to be limited only by the spirit of this invention and the scope of the a pended claims.

at is claimed and desired to be secured by Letters Patent is:

1. In a lock structure having a front plate, a movable latch bolt extending therethrough, a strike plate, an opening formed through said strike plate to receive said bolt when the lock is in the closed position and an outwardly projecting flange adjacent each end of said fggnt and strike plate respectively disposed to overlap intermediate said plates when the lock is in the closed position.

2. In a lock structure, a strike plate having a bolt-receiving opening therethrough; a front plate having a bolt-receiving opening therethrough; a box-like housing projecting from one side of said strike plate to receive said bolt when the same passes through the opening in the strike plate; three sides of said housing projecting from the opposite side of said strike plate to form flanges around three sides of the said hole through the strike plate; and outwardly projecting flanges around four sides of the hole through said front plate, said front plate flanges being partially circumscribed by the strike plate flanges when the lock structure is in a closed position.

3. In a lock structure, a strike plate having a bolt-receiving opening therethrough; a front plate having a bolt-receiving opening extending around all but one side of the strike plate 5 closed position.

opening; an outwardly extending flan e extending around all sides of the opening m the front plate, said flanges being adapted to overlap each other when the lock is in the In testimony whereof I hereunto aflix my signature.

GORDON L. ROSS. 

